The use of CNC centers is well established in the machining of work pieces in order to efficiently produce machined items of considerable complexity and where the machining requires a number of actions to be applied to the work piece to produce the completed item. Generally such centers comprise a chuck which supports the work piece and is able to cause rotation of the work piece. The chuck is associated with a tool head which is movable into and out of a working relationship with the work piece. The tool head has access to a magazine of tools and is able to extract a tool from the magazine of tools according to the machining required and apply the tool to the work piece whilst the work piece is caused to rotate to achieve the desired configuration of the final product.